Per-user GITHUB_ACCESS_TOKEN

[suculent]

ENV var in tests.

Otherwise, User should be able to insert/update his access token somewhere in Profile screen.

Upon entering, token is validated with GitHub and used to push first available RSA key to GitHub. If key is not available, it will be created.

So entering GHAT (github access token) ensures communication with GitHub without creating RSA Key manually (this remains for other GITs).

[suculent]

Added, unit-tested, just not integrated yet. The token storage should be Vault.